move code size benchmark to separate directory

morphisms/length_prefix.morphism-base

@@ -0,0 +1,24 @@
+morph_array_as_valterm_to_lenpfx (Terminator:x86.UInt8)
+    <Seq~<ValueTerminated Terminator> x86.UInt8>
+--> <Seq~<LengthPrefix x86.UInt64> x86.UInt8>
+```
+    length_prefix_uint8_array_clear(dst);
+    while( *src != Terminator ) {
+        length_prefix_uint8_array_push(dst, *src);
+        src++;
+    }
+
+    return 0;
+```
+
+morph_array_as_lenpfx_to_valterm (Terminator:x86.UInt8)
+    <Seq~<LengthPrefix x86.UInt64> x86.UInt8>
+--> <Seq~<ValueTerminated Terminator> x86.UInt8>
+```
+    for( uint64_t i = 0; i < src->len; ++i ) {
+        *dst ++ = src->items[i];
+    }
+    *dst = Terminator;
+
+    return 0;
+```